[NUCLEO_F207ZG] Conflict with Arduino D11 and Ethernet port

The board has a jumper that be used to select between using ethernet
or using SPI for the same pin.
Without this patch, a user that configures the board in 'SPI' mode
would get a "pinmap not found for peripheral" error.
With this change a user doesn't have to change the mbed library
when switching modes
(of course user has to take care of SW and HW matching...
SPI wouldn't work as expected if board is configured in Ethernet)

Author: jeromecoutant

hal/targets/hal/TARGET_STM/TARGET_STM32F2/TARGET_NUCLEO_F207ZG/PeripheralPins.c

@@ -255,7 +255,7 @@ const PinMap PinMap_UART_CTS[] = {
 //*** SPI ***
 
 const PinMap PinMap_SPI_MOSI[] = {
-//  {PA_7,  SPI_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_SPI1)}, // Ethernet RMII RX Data Valid
+    {PA_7,  SPI_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_SPI1)}, // Ethernet RMII RX Data Valid // D11
     {PB_5,  SPI_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_SPI1)},
 //  {PB_5,  SPI_3, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF6_SPI3)}, // choice: PB_5 with SPI_1
     {PB_15, SPI_2, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_SPI2)},

hal/targets/hal/TARGET_STM/TARGET_STM32F2/TARGET_NUCLEO_F207ZG/PinNames.h

@@ -235,7 +235,7 @@ typedef enum {
     USBRX       = SERIAL_RX,
     I2C_SCL     = D15,
     I2C_SDA     = D14,
-    SPI_MOSI    = D11,
+    SPI_MOSI    = PB_5, // Conflict between D11 and RMII RX Data Valid (PA7)
     SPI_MISO    = D12,
     SPI_SCK     = D13,
     SPI_CS      = D10,